Froth flotation apparatus or pump device



Dec. 3, 1968 D. FRAZER 3,414,245

FROTH FLOTATION APPARATUS 0R PUMP DEVICE Filed May 7, 1965 2 Sheets-Sheet 1 5 FIG INVENTOR. DAVID FRAZER ATTORNEY Dec. 3, 1968 D. FRAZER Filed May '7, I965 2 Sheets-Sheet 2 J i E I INVENTOR. I42 DAVID FRAZER BY! I ATTORNEY United States Patent O 3,414,245 FROTH FLOTATION APPARATUS R PUMP DEVICE David Frazer, 247 Lakeshore Drive, Apt. 4, Toronto, Ontario, Canada Filed May 7, 1965, Ser. No. 454,057 4 Claims. (Cl. 261-437) ABSTRACT OF THE DISCLOSURE Froth flotation apparatus having an impeller which discharges gas at the periphery of the impeller, the gas passing by way of a hollow shaft and passage in the impeller, and an inverted cup movable to and away from the impeller for regulating the recirculation of the pulp and also for admitting slurry from an inlet source. An additional feature is that the appartus may be used as a pump.

My invention primarily concerns froth flotation apparatus and aims in this respect to provide a more eflicient and readily controllable apparatus of this kind whereby the amount of recirculation pulp is readily regulatable as well as the volume of air introduced in the pulp. Moreover, according to the arrangement, the apparatus brings about uniform distribution of air and provides for a more desirable air-pulp mixture which is thoroughly diffused by intense pressure by the impeller action to bring about increase in effective aeration.

According to the arrangement recirculation of pulp is regulated in a simple and practical manner by means of a manually-adjustable gap set up between two members, one of which is movable to-and-away from the other whereby to regulate the recirculatory flow to the impeller and also to admit slurry from an inlet source.

The structure provides for flotation efficiency through promoting direct contact of all mineral particles with aeration bubbles, and forcible contact is achieved in order to assure air-bubble attachment to the chemically-coated particles.

The structural arrangement also includes bafling means to retard swirling action induced by rotation of the impeller. Another feature of the invention is that it acts to keep pulp levels higher in each adjoining cell thereby tending to eliminate the need of pumping pulp at the end of the flotation circuit.

Other objects and advantages of the apparatus for froth flotation will appear to those skilled in the art.

A further use of the apparatus is in the separating of gases or vapours by washing. Additionally, the use of the apparatus as a pump serves for blending and mixing different materials and also to wash off reagents at the end of a flotation circuit while at the same time raising the level of pulp sufficiently to continue with the next process. It will, therefore, be understood that the invention is not intended to be restricted to its primary use of that of a froth flotation apparatus as more particularly disclosed in the ensuing specification and shown in the accompanying drawings, in which:

FIG. 1 is a vertical sectional view of a cell unit for a froth flotation system;

FIG. 2 is a sectional plan view taken on line 2-2 of FIG. 1;

FIG. 3 is a sectional detail of the impeller structure taken on line 33 of FIG. 1;

FIG. 4 is a section on line 4-4 of FIG. 1 showing parts of the gap-adjusting means for controlling recirculation; and

FIG. 5 is a sectional detail on line 55 of FIG. 2 showing the trough or froth overflow.

Now referring to the drawings in detail, a cell is generally denoted at 8 which is of ordinary construction and may form a part of a multiple-cell tank as is well known in the art. The cell comprises side walls 10 and a bottom wall 12. The cell provides a chamber 14 for liquid having a froth overflow lip 16 supplied at one of the side watlils5 and flanking the trough 18, as shown in FIGS. 2 an A suitable superstructure 20 is located above the cell 8 and supports the vertical shaft 22 which is a hollow member journalled for rotation. A pillow block bearing 24 is fixed on the superstructure 20 to mount the shaft 22 and at the upper side thereof is a thrust collar 25 fixed on the shaft. The shaft will have another supporting bearing (not shown) which may be, for instance, located at the lower end thereof; however, this is simply a matter of engineering design and will need not be dealt with further.

Shaft 22 carries at its upper end a pulley or sheave 26 in driving connection with a motor or other prime mover (not shown). A gas supply header or other means supplies the aerating gas and for this purpose there is provided a connection for the upper end 28 of the hollow shaft 22 with a line or conduit (not shown) as will be well understood in the art.

The rotary impeller unit, generally denoted at 30 is mounted at the lower end of the shaft 22 to rotate therewith and this end of the shaft is diametrically enlarged as at 32 for a short distance, as clearly shown in FIG. 1. An end Wall 34 serves to seal off the shaft at its lower end and this end wall is formed by a plate attached to the impeller 30.

The impeller 30 is shown as comprising the lower disc 36, the upper disc 38 and the intervening radial blades 40 alongside of each of which is a tube 42, which has an inner end communicating with the bore of the enlarged portion 32 of the shaft 22. Chambers 42 are disposed at the trailing side of the blades 40 and have their outer ends sloped backwardly as at 44. As will be appreciated, the rotational effect of the impeller producers suction in the shaft 22 and tubes 42 discharge gas at the periphery of the impeller in close proximity to the blades and thus serves to create a trailing zone of highly gaseous matter at the end of each blade.

The radial blades 40 are united with the discs 36, 38, and it will be noted that the upper disc 38 is of a somewhat less diameter than the lower disc.

Surrounding the lower end of the shaft adjacent the impeller is a cylindrical sleeve 46 which provides a circulatory passage 48 for pulp, which communicates with the peripherally open spaces 50 of the impeller, which are segregated by the blades whereby the pulp is not only discharged from the impeller centrifugally but is subject to impinging action of the gas discharged from the radial tubes 42. Thus forcible contact is made with gas to bring about the desired bubble attachment to the chemicallycoated mineral particles. The vortex of gas and pulp formed by the vacuum created at the periphery of the impeller sets up the conditions necessary for good flotation.

From the foregoing it will be seen that the pulp in recirculating is drawn into the cylindrical sleeve 46 by the impeller and then peripherally discharged from the spaces 50 of the impeller. The rate of recirculation and regulation thereof is controlled by the provision of a variable entrance gap 52 leading to the flow passage 48 of the sleeve 46. A confronting cup 54 co-acts with the sleeve 46 to provide the gap 52, Said cup is a movable cylindrical member having its upper end substantially closed by a wall 58 freely surrounding the shaft 22 and pierced to freely receive the same.

The gap-adjusting member 54 is movable to-and-away from the adjacent end of the sleeve 46 by exterior adjusting means 60. The gap-adjusting member 54 is guided for movement axially of the shaft 22 by feather keys 62 which are made a slide fit in slots 64 respectively formed by guide elements 66. The guide elements 66 are vertically arranged and secured on transverse bafile members 68 which extend across the cell intermediate the height thereof and are secured to opposite side walls thereof.

Means 60 for adjusting the proximity of the member 54 with respect to the sleeve 46 comprises a suspension rod 70 having its lower end secured to the gap-adjusting member 54 as at 72 and having its upper end screw threaded as at 74 and threadedly engaged with a hand wheel 76 or the like which bears against a bracket plate 78 secured on the support 20.

Accordingly, it will be manifest that the member 54 may be moved away from the member 46 by turning the wheel in one direction and may be shifted toward the member 46 by turning the wheel in the other direction.

The discharge indicated at 80 in FIG. 1 is shown as part of a weir device which does not concern the present invention.

An important feature of the invention is that the gapcontrol means for recirculation is associated with slurry inlet 82 for the feeding of the material into the cell as required. This includes an inlet pipe 84 extending through a wall of the cell 8 and leading to a remote source of supply. The inner end of pipe 84 extends through side wall portion of the member 54 for discharge therein, and to this end an aperture 86 is cut in the side Wall member 54 to receive the adjacent end of pipe 84 and allow it to have required angular movement in a vertical plane as may be necessitated by angular adjustment of the member 54. A shoe 88 of pliant material, such as rubber, plastic or comparable material, serves as a connecting means for the pipe 84. It will be understood that other types of connections may be resortet' to within the scope of the invention. The introductory pipe 84 is shown as having a swivel juncture with adjacent side wall portion of the cell as by means of a ball 90 sleeved on the pipe 84 to move therealong in sealing engagement. The hole 92 in this wall portion is shown as fitted with pliant shoes 94 at opposite sides of the wall which engage the wall in a sealing relation to seal the joint against leakage. While this arrangement is satisfactory other expedients could be used if so desired.

From the foregoing it will be manifest that slurry introduced into the cell will flow into the gap-adjusting cup 54 then into the flow passage 48.

As has been referred to earlier, apart from the use of the invention in the flotation process it has utility also in washing or separating gases where one is soluble in a solution, for ef'ample, lacquer fumes which can be removed from the air by drawing the fumes through the tubes 42 of the impeller and discharging the same into an absorbing solution. The method would be similar to the flotation process and would assure the eflicient absorbtion of the fumes by the solution contained within the cell. The apparatus of my invention would also serve for blending and mixing different materials and at the same time functio ing as a pump for at least one of the materials.

What I claim is:

1. Froth flotation apparatus comprising a cell for containing 21 body of iquid, a hollow shaft depending therein and supported for rotation, means for driving said shaft, an impeller secured on the lower part of said shaft and including spaced discs within intervening radial blades, said shaft having its lower end closed off and in communication with radial passages provided in the impeller for discharge of aerating gas from said shaft, said shaft having an upper end in communication with a source of gas supply, a sleeve encircling the lower end of said shaft and upwardly extending from said impeller, said sleeve providing a flow passage in communication with centrifugal discharge passages between said blades, an inverted cup member encircling said shaft and spaced from said sleeve to provide a gap for pulp to enter said sleeve for recirculation, means for adjusting said cup member axially of said shaft to vary said gap for control of recirculation, and an introductory tube extending through said cell and into said cup for delivery of slurry, and connecting means for said introductory tube devised to accommodate adjustment of said cup member.

2. The apparatus of claim 1, said cup supported between baffies by guide means which constrain it to movement axially of said shaft.

3. Apparatus of the kind described, comprising a vessel for containing a body of liquid, a driven shaft depending into said liquid, impeller means secured on the lower end of said shaft for effecting centrifugal discharge of liquid, said impeller means comprising spaced upper and lower disc with intervening radial blades, said upper disc having a cut-away portion which provides a central opening for receiving liquid to be discharged, means providing a flow passage in communication with said opening, said flow passage being supplied by an annular sleeve encompassing said shaft and made rigid with said upper disc, regulating means for controlling flow of liquid to said flow passage, said regulating means including an inverted cup encompassing said shaft and guidably supported for movement to and awa from said sleeve, said cup having spaced relation with the adjacent end of said sleeve to provide a gap for flow of liquid into said flow passage of said sleeve, said gap being variable by changing the position of said cup, and an introductory tube extending through a wall portion of said vessel and into a side wall portion of said cup.

4. The apparatus of claim 3, said introductor tube being mounted to accommodate movement of said cup.

References Cited UNITED STATES PATENTS OTHER REFERENCES Denver Sub-A Flotation, Denver Equipment Company, Denver, Colo., pp. 10-12. (Received Jan. 1, 1955, copy in 261/87) Bulletin No. F10-B29.

HARRY B. THORNTON, Primary Examiner.

E. H. RENNER, Assistant Examiner. 

